Regenerative braking system for electrically-driven vehicles



H. LfiBEcK REGENERATI VE BRAKING SYSTEM FOR ELECTRICALLY DRIVEN VEHICLES Filed Dec. 28 1918 Invzni'or a n 5 m y B Patented Oct. '2,

PATENT oFFicrmama nfinncx, or-nEn'sEaUnswEnnn; I

BEGENERATIVE BRAKING SYSTEM FOR ELECTRICALILY-DBIVEN Application filed Decemberz8,,-1918. Serial 110. 268,113.

To (113 whom it may concern: I

Be it known that I, HILDING Lennon, subject of the King of Sweden, residingat Herserud, Sweden, have invented certain new and useful Improvements in Re enerative Braking Systems for Electrical y-Driven Vehicles, of which the following .is a specification. I

The present invention relates to a method of utilizing the otential and kinetic energy of electrically riven vehicles, particularly such using storage batteries, in running downhill or in changing rapidly-to a .lower speed, by transforming said energy into electrical energy, for instance for charging the storage battery, whereby at the same time the brakingof the vehicle is effected.

'. More particularly the invention relates to.

such known systems of this kind in which the driving motor may be 'made to act as a generator by connectingthe field winding of the motor in parallel with a separate source ofcurrent supply for the purpose of obtaining suitable field-strengt In a known system said source of currentsupply consists of a separate storage bat te" containing a few cells and having an ad ustable resistance connected inserieswith it, and in another known system the :source of current supply consists of a .separate small motor-generator,;the motor-of which is driven from the main storage battery and.

the speed bf which may be regulated by .means of an adjustable TBSlStfiIlCGlDSGItBd in:

the motor circuit, thegenerator o'fsaid-motor-generator being connected in parallel with thefield winding of the driving ,motor.

According to the present invention a separate small generator is used as a source of current supply, saidgenerator, however, as

beingdriven and regulatedmechanically by means ofany suitable transmission directly or indirectly connected with-the "shaft of the driving motor or a wheel aXleofthe vehicle. I -s The inventionlwill be art aa p (1e; scribed with reference to the accompanyingdrawing. Fig. 1 shows. diagrammatically gram'showing the electricalconnections beg,

tweenthe main source of current su .ply,, --'-for instance a storage battery I), gan] the driving motor and between the generator :9 an th e dwin ing' m3. :-:-th during;

an embodiment of an arrangement accord= ing to the invention, and Fig. a circ'uit, dias spring y h. i

aruns-ve -slowl a -means 0' asmec anlcal brake. A

motor. Fig; .3 isa section through the'apparatus' taken in a plane between the generator gand the disk 0. v

Fig. 4 is anenlar d fragmentary detail view of the lever s s owing therebky. Y a

In ig. 1 m is the. drivingmotor. and g the enerator. Fixed to the shaft a, of the driving motor is av brake disc c-the plane outer side of which is preferably formed to serve as .a friction disc. The generator 9 maybe rigidly attached to the motor m in any suitable way. Providedon an extension d of the vshaft of the. generator is a the cam carried slidable friction wheel e which CflIl'bQ'IIlOVGd longitudinally on the said extension d b periphery of the friction ,disc. Thejfriction' wheel is held against-the friction disc with a suitable pressureby means of a The friction vdisc suitably have a recess'in its centreqin-gorder that the friction wheel shall not bear against the disc when in a position opposite, to the centre :ofv the disc. The shaftof the" generator tis'preferv ably connected with ;the extension d by means of a universal joint 21. -By displacing the friction wheel the fgeneratoiymayobvlously at a certain speed-ofthe driving moto be run at any speed between certa n maximum and minimum limits j The lever f is ivoted at 7' and rigidly ,;connectedwiththe every/h the .latter .bein connected e-for in- :stance by means of am or a wire-hwith a lever n which is .pivotedzat; =0 and rigidly connected with the; pedal 42., friction wheel e is held in neutral position by the sp in 9- a, I

By electrical braking bymeansof the arran ement above described; the speed of the vehicle may be slowed down till the vehicle vwhen: w wybes piie y The mechanical, brake ma for instance be so arran d thata brake; andm acts on :the brakedisc 0on x-tnrningalever 8 connected with 'the ilever a of the pedal gp by ,means of-the rod or wire 1a. When:the ;lever a-is not u eda y the r p d wi 1, e d y a,

spring v.t i n suchs a position 'that. -the brake bend r it -t ontw it thekb iek dis "h .od .l' ;i conne ted. w t earr n f =Si ch =1 te ionithfl -i s 5- m teri ly stretched until the lever k has ,been stopped 7 by an abutment w. The rod a has two collars 3 and a located on opposite sides of the lever s and so arran ed that the lever s is not actuatedby the ar a on operating the pedal until the lever k is stopped by the abutment a). By means of the lever s and aswitch to the main circuit is opened before the.

brake band 1' is applied to the brake disc 0, and a suitable switch 20 is preferably interposed in the electrical connection between the field winding m ofithe driving motor m and the generator 9 forhutting the lattervout of the main circuit during the periods when the motor m is used for driving the car.v

The electrical and mechanical brakes opcrate as follows v on pushing the pedal p from position 1 to position 2 the lever n is moved from position 4 to position 5, and the lever k is actuated by the rod land the spring '0 and moved from position 7 to position 8 in which it isstopped by the abutment a, the spring '0 bein .then stretched only very little, and, furt er, the lever f is moved from osition 9 to position 10 the friction wheel e heing then moved from neutral position to the maximum speed position. The mechanical brake is not actuated at all on pushing the pedal fromposition 1 to position 2 but the collar 2 is displaced to bear against the lover 8 without yet 0 crating the latter. On pushing the pedal rom position 2 to position '3 the main circuit is first opened at w by the lever s and then the latter applies" the brake band, The lever k then remains in position 8, i. e., bearing against the abutment :1: and the spring-o is stretched by the bar 1 to the extent required for the lever n to move from position 5 to position 6.

w "allows the pedal 1) who moved so far as to When the pedal p is released the operations described take place in the reversed order. Thus, the lever on is returned by the spring t the brake band 7' bein then released from the brake disc '0, an then the main circuit is closed at w. The lever is 'is returned by the spring g from position out of contact with t'he disc when the latter is at rest. v a

As seen from the above description, the means for operating the brakes are so deoperateIthelever '8. It will be understood that under conditions of normal running, Y with the friction wheel e at the center of therevolving friction disc '0, said wheel will not reyolve, and the generator g'will be out of action. When it 1s desired to brake the inmate car, as in oing down hill, or in slowing down, the riction wheel e is moved to an eccentric position as described above, causing this wheel, and the enerator 9 connected with it, to be driven y the rotating disc 0. However, under these circumstances, the power for rotating the disc 0 is derived, not from the electric current furnished to the motor m, but from the potential or kinetic energy of the moving car, whichenergy-or momentum tends to keep the car in motion. According to the position to which the wheel 0 is shifted, the rotary speed of the generator 9 will be greater or smaller, and the voltage furnished by this generator will increase gradually as the'speed of the generthe voltage of the said motor can be increased enough to overcome the voltage of the battery, so that the'imotor will'return current into the battery, the motor acting as generator. The main circuit is not broken at the switch w until the electrical braking action has progressed far enough to render it expedient-to completethe braking action by the efieot of the mechanical brake. Of course at the time the mechanical brake comes into. action, the electric circuit should be open.

It will be undcrstoodthat the action of re eneration or recharging can take place on y as long as the speed or momentum of the car is high enough to furnish the potential or kinetic energy required to run the motor (then acting as a generator) at a speed suflicient to hiring the voltage of the current thus generated above the voltage of the battery. It is well-known that a regenerative or rechargin action vof this general. character has a raking efiect on the car. 7

, The invention is not limited to the shown arrangement for eltecting a variable translIllSSlOn from the shaft of the motorm to theshaft of the generator 9' as the transmlSSlOIi, evidently, may be efi ected in other ways, for instance by means of beveled rollers connected by a belt, or by means of gearings, etc. Also other parts may be con structedsin many difierent ways." i

The arrangement may also be used, suitably modified, when several motors are used on the vehicle.

The method of braking by applying an electrical and a mechanical brake after one another may, evidently, also beusedin connection with other regenerative systems than that above described, for instance in connection with systems in which the ener- Ill) gization of the motor is effected by means of a separate battery or a motor-generator.

Although the invention is chiefly intended for motor cars it is evident that it may be applied also to other electrically driven objects where a regeneration of electrical energy can be effected by the motor being connected as a generator, for instance lifts, cranes or the like.

I claim 1. In a regenerative braking system for electrically driven vehicles the combination with the drivingmotor, of a generator connected across the field winding of the motor and means for mechanically driving said generator from the shaft of the motor, said means comprising a variable transmission device for varying the speed of the generator.

2. In a regenerative braking system for electrically driven vehicles the combination, with the driving motor and a source of current supply therefor, of a generator connected in parallel with the field winding of the motor, for causing said motor to act as a generator, a mechanical brake, a common controlling device for said generator and brake mechanically connected with the mechanical brake and means for operating the generator and the brake, one after another, by means of said controlling device, the generator being first brou ht into operation and the the mechanics. brake.

ii In a regenerative braking system forv electrically driven vehicles the combination, with the driving motor and a source of current supply therefor, of a generator con-. nected in parallel with the field winding of the motor, for causing said motor to act as a generator, a mechanical brake,.a common controlling device for said generator and brake mechanically connected with the mechanical brake and the generator and the brake after one an-. other by means of said controlling device,

means for operating V said means being arranged soas to allow the mechanical brake to be operated even if the generator be, out of operation.

4. In a regenerative braking system for electrically driven vehicles the combination with the driving motor, of a generator connected across the field winding of the motor, means for mechanically driving said generator from the shaft of the" motor, a variable transmission device for varying the speed of the generator and means for operating said transmission device consisting of a. brake operating lever, and a mechanical brake operable by said brake operating lever.

5. In a regenerative braking system for electrically driven vehicles the combination of an electric brake consisting of the driving motor and a generator connected across the field winding of the motor, a variable me chanical transmission for driving said generator from the shaft of the motor, a mechanical brake, a brake operating lever, means for operating said brakes after one another by means of said brake operating lever the electric brake being first brought into operation and then the mechanical brake.

6. In a regenerative braking system for electrically driven vehicles, the combination with the driving motor, of a generator connected across the field winding of the motor, means for mechanically driving said generator from the shaft of the motor, a variable transmission device for varying the speed of the generator, means for operating said transmission device consisting of a pedal,

and a, mechanical brake operated by said pedal.

' In testimony whereof I aflix my signature in presence of two witnesses.

HILDING LIlBECK.

Witnesses.

Atjsnn'r K. PARKER, Hanan Loam, 

